sdio_memcpy_fromio(9)

✨ sdio_memcpy_fromio — the "gimme that data" page 💖

okay so bestie, welcome to the sdio_memcpy_fromio manual page, part of the Kernel API Manual. if you've ever needed to yoink a chunk of memory out of an SDIO function and drop it into your own buffer, this is literally the function for you. no cap. 🎀

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🌸 SYNOPSIS 🌸

int sdio_memcpy_fromio (struct sdio_func *func , void *dst , unsigned
int addr , int count );

like… that's the whole vibe. one function, four things to give it, one int back. slay. 💅

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🦋 ARGUMENTS 🦋

• func — the SDIO function you wanna access. this is your main character. 👑
• dst — the buffer where the data is gonna live. the destination of the glow-up, if you will. ✨
• addr — the address to begin reading from. where the journey starts. 🌈
• count — number of bytes to read. how much snack to grab. 🍓

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💜 DESCRIPTION 💜

so what does it actually do? it reads from the address space of a given SDIO function, bestie. that's it, that's the whole thing. 🫶

the return value tells you if the transfer succeeded or not — so like, check it, don't just assume it ate. 😭

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🔥 SEE ALSO 🔥

the kernel file lives at ./drivers/mmc/core/sdio_io.c, and honestly the whole friend group is iconic, so here's everyone you should also go say hi to:

• sdio_claim_host(9)
• sdio_release_host(9)
• sdio_enable_func(9)
• sdio_disable_func(9)
• sdio_set_block_size(9)
• sdio_align_size(9)
• sdio_readb(9)
• sdio_writeb(9)
• sdio_writeb_readb(9)
• sdio_memcpy_toio(9)
• sdio_readsb(9)
• sdio_writesb(9)
• sdio_readw(9)
• sdio_writew(9)
• sdio_readl(9)
• sdio_writel(9)
• sdio_f0_readb(9)
• sdio_f0_writeb(9)
• sdio_get_host_pm_caps(9)
• sdio_set_host_pm_flags(9)
• sdio_retune_crc_disable(9)
• sdio_retune_crc_enable(9)
• sdio_retune_hold_now(9)
• sdio_retune_release(9)

like, the whole squad fr fr. go read them. iykyk. 💀

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and that's the page!! mwah 💋 — brought to you by the fine people over at ./drivers/mmc/core, dated October 2026, for the Kernel API Manual. go read some memory, bestie. 🌟🎀💖